Apparatus for moisture absorption

ABSTRACT

A moisture absorption apparatus comprises a desiccant container with a side wall and optionally a bottom and a desiccant solution container with a side wall and a bottom. The desiccant container receives particulate desiccant which forms a desiccant solution on contact with moist air. The desiccant container side wall has at least one air access opening and a passage permitting desiccant solution to flow into the desiccant solution container. The desiccant solution container has a top opening and is slidingly displaceable on the desiccant container so as to allow the desiccant container to be displaced in the desiccant solution container to a depth sufficient for the desiccant solution container side wall to fully cover the air access opening of the desiccant container.

FIELD OF THE INVENTION

The present invention relates to the field of dehumidification, inparticular to a moisture absorption apparatus provided with a desiccantin an upper chamber. More particularly, the present invention relates toa moisture absorption apparatus for keeping the atmosphere in atransport container in a dry state.

BACKGROUND OF THE INVENTION

The present invention departs from the tubular moisture-absorbingapparatus disclosed in U.S. Pat. No. 5,676,739 (Gustafsson) designed forvertical disposition in, for instance, a closed steel container fortransport of humidity-sensitive goods. The apparatus is made of apolymer coated board which provides required stiffness. Starting fromits upper end, it comprises, in a longitudinal direction, a chamber witha moisture-absorbing material, such as calcium chloride, which forms anaqueous solution on contact with humid air. The salt solution iscontinuously drained into a lower liquid collection chamber in form of aplastic container with which the upper chamber is in communication. Theparticulate desiccant material is retained in the upper chamber by sievemeans comprising a non-return valve means. Contact of the desiccant withambient air is ensured by a netting element located in front of anopening in the wall of the upper chamber. The netting element isdesigned to prevent the aqueous solution from leaving the upper chamberthrough it rather than through the sieve means. Prior to use the nettingelement and thus the opening in the wall of the upper chamber is closedby a removable plastic foil.

While the moisture-absorbing apparatus of Gustafsson has been shown tofunction well in industrial practice, there is room for improvement. Inparticular, the known apparatus is bulky. This is a disadvantage intransport and storage prior to use.

OBJECTS OF THE INVENTION

A primary object of the present invention is to provide an apparatus ofthe aforementioned kind which is less bulky than known devices of thiskind and, therefore, easier to store and transport.

Further objects of the invention will become evident from the followingsummary of the invention, the drawings, the description of preferredembodiments, and the claims.

SUMMARY OF THE INVENTION

According to the present invention is disclosed a moisture absorptionapparatus for keeping the atmosphere in a transport container in a drystate, comprising a desiccant container having a side wall, optionally abottom and means to retain the desiccant in the container, furthercomprising a desiccant solution container having a side wall and abottom, the desiccant container being capable of receiving desiccantwhich forms a desiccant solution on contact with moist air, thedesiccant container side wall having at least one air access opening anda passage permitting desiccant solution to flow into the desiccantsolution container, the desiccant solution container having a topopening and being slidingly displaceable on the desiccant container soas to allow the desiccant container to be displaced in the desiccantsolution container to a depth sufficient for the desiccant solutioncontainer side wall to fully cover the air access opening of thedesiccant container, the apparatus further comprising means to preventseparation of the desiccant container and the desiccant solutioncontainer.

It is preferred for the separation preventing means to comprisecooperating circular flanges of the desiccant container and thedesiccant solution container. It is particularly preferred for theseparation preventing means to comprise barbed profiles. Also preferredare snap connections that can be opened to allow separation of thecontainers, in particular for emptying the desiccant solution container.

Also other separation preventing means are conceivable, such as aflexible element, such as a string or cord (which may be elastic enoughto allow temporary separation of the containers for emptying), securedat its respective ends at the container bottoms.

Preferably the desiccant container and the desiccant solution containerare of generally cylindrical or parallelepipedal form. It is alsopreferred for the the moisture apparatus of the invention to comprisemeans for fastening it to a wall of a transport container.

In a pre-use condition, the desiccant container is inserted into thedesiccant solution container at least far enough to make the lattercover the air access opening of the former to be fully covered. Therebythe desiccant is protected against the action of moist air. Thereby thedesiccant solution container acts as a protective cover corresponding tothe removable plastic foil of the prior art apparatus referred to above.

When making the apparatus of the invention ready for use, the apparatusis placed in an upright position, that is, for instance, with the bottomof the desiccant solution container resting on a support surface, andthe desiccant container is lifted out of the desiccant solutioncontainer. Cooperating holding means, such as, for instance, holdingmeans disposed at the outer wall of the desiccant container and theinner wall of the desiccant solution container prevent the containersfrom being fully separated. It is preferred for the holding means of thedesiccant solution container to exert a sealing function in a pre-usestate.

The apparatus of the invention may be designed for single or multipleuse. In case of a single-use design, the apparatus is provided with theclosed desiccant container filled with a charge of desiccant. In suchcase the desiccant container may comprise two openings or sets ofopenings only: one in its side wall for air access, the other at itsbottom for escape of desiccant solution. In a pre-use condition, thedesiccant container is inserted into the desiccant solution container atleast far enough to make the latter cover the air access opening of theformer to be fully covered. Thereby the desiccant is protected againstthe action of moist air. Thereby the desiccant solution container actsas a protective cover corresponding to the removable plastic foil of theprior art apparatus referred to above.

The containers can be made from any suitable polymer material, such ashigh density polypropylene, polyvinyl chloride, polystyrene orpolyvinylacetate.

In case of a multiple-use design, the desiccant container in additioncomprises a refill opening, preferably disposed at its top section,provided with a screw lock or similar.

It is within the scope of the invention to provide the desiccant eitherin particulate free flowing form or in form of a refill cartridgepermeable to moist air and desiccant solution, such as a filter paper ornon-woven polymer cartridge. The moisture apparatus for multiple usecomprises a through opening in the top portion of the desiccantcontainer closed by a removable plug or similar. Also preferred is tofill the desiccant container through the air access opening in its sidewall. This opening can be provided with a desiccant retaining net orgrid, such as a net or grid fixed to a frame which can be mounted by,for instance, snapping onto the desiccant container side wall at thearea surrounding the air access opening. A preferred variant is to makethe desiccant container in two parts, a trough-like part in which oneshort end (the lower or bottom end in use) is a perforated wall throughwhich the desiccant solution passes into the desiccant solutioncontainer, and a lock-like part comprising the air access opening. Thelock part can be snapped on the trough part after filling with desiccantand can be unsnapped after use for loading again with desiccant.Particularly preferred is this two-part design of the desiccantcontainer when the latter takes a parallelepipedal form.

It is preferred for a multiple-use apparatus of the invention tocomprise a desiccant solution emptying through opening in the bottom ofdesiccant solution container closed by a removable plug or similar.Alternatively the desiccant solution container may be emptied bytemporarily separating it, fully or partially, from the desiccantcontainer.

The moisture absorption apparatus of the invention preferably comprisessealing means disposed at the desiccant solution container wall, inparticular at the inner face of the desiccant solution container sidewall in the vicinity of the top opening.

Preferably the desiccant container and the desiccant solution containersare of oblong shape, for instance, tubular shape. In this context,“axial(ly)^(.)” refers to the desiccant or desiccant solution containeraxis. Since the apparatus of the invention is designed for use in anupright position, “top” and bottom” refer to this working position. Theapparatus is kept in the working position by, for instance, a wirefastened at an eye provided at the upper end of the desiccant containerand, with its other end, at a suitable point of fixation at the innerwall of a steel container or other compartment.

A preferred deliquescent desiccant is calcium chloride or desiccantmixtures containing calcium chloride but, in principle, all desiccantsbecoming deliquescent on contact with humid air can be used. The aqueoussolution of the desiccant flows through the bottom opening(s) of thedesiccant container into the desiccant solution container. Non-returnvalve(s) may be arranged at the bottom opening(s) but this is of noimportance for the performance of the apparatus of the invention; its(their) only function is to prevent liquid from flowing back from thedesiccant solution container to the desiccant container and out fromthere in the event the apparatus falls on the floor by the suspendingwire breaking or coming loose. Preferably the desiccant is constitutedby free-flowing particles. It may also advantageously be provided inform of a cartridge filled with particulate desiccant, the cartridgehaving walls permeable to atmospheric humidity and aqueous desiccantsolution.

According to a preferred aspect of the invention the air access openingarea is variable to adapt the apparatus of the invention to variousdrying needs. A large area provides a high drying rate, whereas asmaller area provides a lower drying rate. A high drying rate ispreferred in applications where the humidity shall be lowered quickly,for instance, after loading a transport container in a tropical humidclimate. Since it is, however, not necessary for most applications toprovide a relative humidity in the transport container of below 75%,except for some applications for which a relative humidity below 50% isrequired, the long-term maintenance of a large-window version of theapparatus of the invention would keep the humidity in the transportcontainer at an unnecessary low level which economically unsound. Forlong-term maintenance of an adequate humidity level, such as humiditylevel between 50% and 75%, the use of an apparatus with a smaller airaccess opening according to the invention is adequate and preferred. Itis within the scope of the invention to provide a set of apparatus ofthe invention comprising a number of such apparatus which differ inregard of their air access opening area. It is also feasible andpreferred to provide an apparatus of the invention with a variable airaccess area; this variation can be accomplished by, for instance, aplate which is disposed slidably over the air access opening area inparallel guide profiles attached externally to the desiccant containerside wall on either long side of the air access opening.

The same result can also be obtained by using the desiccant solutioncontainer as an air access opening shielding means. Thus, according toanother preferred aspect of the invention, the desiccant solutioncontainer is fixable at a position in which it partially shields the airaccess opening.

According to still another preferred aspect of the invention a set ofapparatus differing in their air access opening area is provided.

The invention will now be explained in more detail by reference to twopreferred embodiments of the invention illustrated in a drawing.

BRIEF DESCRIPTION OF THE DRAWING

FIG. 1 a shows a single-use first embodiment of the apparatus of theinvention, in a storage state and in an axial sectional view;

FIG. 1 b shows the embodiment of FIG. 1 a, in an active state, in thesame view;

FIG. 2 a shows a multiple-use second embodiment of the apparatus of theinvention, in the same state and view as the embodiment of FIG. 1 a;

FIG. 2 b shows the embodiment of 2 a, in the same state and view as theembodiment of FIG. 1 b.

For the sake of clarity the thickness of the side wall, bottom, and topsection of the embodiments shown in the Figures have been exaggerated.

DESCRIPTION OF PREFERRED EMBODIMENTS

The first preferred single-use embodiment of the moisture absorptionapparatus of the invention illustrated in FIGS. 1 a and 1 b comprises adesiccant container 1 and a desiccant solution container 2 of a slightlyresilient polymer material, such as high density polyethylene. Both areof substantially cylindrical form. The outer diameter of the desiccantcontainer 1 is slightly smaller than the inner diameter of the desiccantsolution container 2 so that it can be inserted in the latter forassemblage; FIGS. 1 a and 1 b illustrate the apparatus in an assembledstate. The desiccant container 1 has a bottom 3 with a number of throughbores 4. Its cylindrical wall 5 comprises large window 6 and joinssmoothly a top section 7 which closes the container compartment 8. Thestop section 8 is provided with ears 9 and eyes 10 for fastening theapparatus by means of a cord or similar to an inner wall of a transportcontainer to be kept dry. The bottom end of the wall 5 is provided witha circumferential flange 11 of a barbed profile of a kind allowing thedesiccant container 1 to be inserted into the opening of the desiccantsolution container 2 which has slightly resilient walls and acorresponding oppositely disposed barbed profile inner circumferentialflange 12 at its top. The desiccant solution container 2 has no openingsother than the one at its top. Once the desiccant container 1 has beeninserted into the desiccant solution container 2 it cannot be easilyremoved because of the cooperating barbed flanges 11, 12 but it can beslidingly displaced in respect of the desiccant solution container 2within the limits set by the flanges 11, 12 and the desiccant solutioncontainer bottom 13. In the FIGS. 1 a and 1 b the tubiform desiccantsolution container side wall is designated by reference number 14 andthe desiccant solution container compartment enclosed by wall 14 and thecontainer bottoms 3 and 13 by reference number 15. In the compartment 8of the desiccant container 1 is disposed a closed bag 16 of plasticnon-woven material containing anhydrous calcium chloride as desiccant;it rests on the bottom 3. The non-woven material is permeable to moistair and aqueous calcium chloride solution formed during the dryingprocess.

The first embodiment of the apparatus of the invention is shown in FIG.1 a in a storage state, that is, in a state in which no drying effect isdesired. In that state, the desiccant container 1 is fully inserted intothe desiccant solution container 2 whereby its window 6 is shielded bythe desiccant solution container 2 from moist air, the flange 12 actingas a seal in that state. The apparatus is activated by drawing thedesiccant container 1 out of the desiccant solution container 2 untilabutment of the flanges 11, 12. Thereby the window allows moist air ofthe environment to pass into the desiccant container 1. This activestate of the apparatus of the invention is shown in FIG. 1 b. In the bag16 aqueous calcium chloride solution is formed by reaction of airmoisture with the desiccant. The calcium chloride solution escaping fromthe bag 16 flows down into the desiccant solution container 2 throughholes 4 in the bottom 3 and assembles on the bottom 13 of the desiccantsolution container 2.

The second preferred multiple-use embodiment of the apparatus of theinvention is shown in FIGS. 2 a and 2 b. The top portion 27 of thecylindrical desiccant container 21 has a threaded opening tightly closedby a fitting screw plug 31 which can be removed for refillingcompartment 28 with particulate desiccant 36. It is also feasible toprovide the multiple-use apparatus with a larger opening for refillingwith a desiccant bag like that of the first embodiment. As in the firstpreferred embodiment the desiccant container 21 is provided with ears 29and eyes 30 for fixation purposes. The window 26 in the side wall 25 ofthe desiccant container 21 is provided with a net to retain thedesiccant particles. The same is true for the through bores 24 in thedesiccant container bottom 23. In the mounted state shown in the Figuresthe desiccant container 21 is inserted in the cylindrical desiccantsolution container 22 in which it is axially displaceable from thetransport or storage position shown in FIG. 2 a in which the window 26is shielded by the side wall 34 of the desiccant solution container 2.At the top rim the desiccant solution container side wall has an innerflange 32 which seals against the side wall 25 of the desiccantcontainer 21. The compartment 35 of the desiccant solution container 22is designed to receive the aqueous desiccant solution formed in thedesiccant container 21. This solution can be emptied through a hole inthe bottom 33 of the desiccant solution container 22. The emptying holeis normally closed by a rubber plug 38, as shown in FIG. 2 b. A polymercord 37 fixed at the plug 38 and the bottom 23 of the desiccantcontainer 21 restricts the displacement of the latter in respect of thedesiccant solution container 22 so as to prevent the containers 21, 22from coming apart. For reasons of clarity the plug 38 and the cord 37have been omitted from FIG. 2 a.

1. A moisture absorption apparatus comprising: a desiccant containerhaving a bottom and a first side wall; the first side wall of thedesiccant container having at least one access opening therethrough; aparticulate desiccant in the desiccant container, the access opening ofthe desiccant container permitting atmosphere outside the desiccantcontainer to enter the desiccant container and contact the particulatedesiccant therein; a desiccant solution container having a second sidewall and having a bottom for retaining a desiccant solution in thedesiccant solution container; a passage from the desiccant containerinto the desiccant solution container to enable flow of the desiccantsolution, which is formed by moisture with the particulate desiccant inthe desiccant container, to flow into the desiccant solution container;the desiccant solution container having a second opening through whichthe desiccant container is slidably displaceable, and the desiccantcontainer being slidably displaceable through the second opening intoand out of the desiccant solution container selectively to a depth whichexposes the access opening to the atmosphere or to a depth in thedesiccant solution container sufficient for the second side wall of thedesiccant solution container to cover the access opening in the firstside wall of the desiccant container and prevent access of atmospherethrough the access opening in the desiccant container first wall toparticulate desiccant therein.
 2. The apparatus of claim 1, furthercomprising cooperating separation prevention devices on the desiccantcontainer and the desiccant solution container for preventing separationof the desiccant container from the desiccant solution container whilepermitting the sliding displacement of the containers with respect toone another.
 3. The apparatus of claim 2, wherein the separationprevention devices comprise cooperating circular flanges on thedesiccant container and the desiccant solution container, the flangesbeing so shaped and positioned as to cooperate and prevent separation ofthe desiccant container from the desiccant solution container.
 4. Theapparatus of claim 2, wherein the separation prevention devices compriserespective barbed profiles on the desiccant container and the desiccantsolution container and the barbed profiles on the containers are shapedand positioned to cooperate to prevent separation of the containers. 5.The apparatus of claim 2, wherein the separation prevention devicescomprise a snap connection between the desiccant container and thedesiccant solution container.
 6. The apparatus of claim 2, wherein theseparation prevention devices comprise a flexible element secured at thebottoms of the desiccant container and the desiccant solution containerand so sized and of such material as to prevent separation of thecontainers.
 7. The apparatus of claim 1, wherein the desiccant containerhas a top; and further comprising: a third opening in the top of thedesiccant container; and a removable plug in the third opening.
 8. Theapparatus of claim 7, wherein the second side wall of the desiccantsolution container has an inner face, a seal at the inner face in thevicinity of the third opening in the desiccant solution container whichis in the passage to receive desiccant solution from the desiccantcontainer.
 9. The apparatus of claim 1, further comprising a removableparticulate desiccant retaining element over the access opening of thedesiccant container.
 10. The apparatus of claim 9, wherein theparticulate desiccant retaining element comprises a net or grid over theaccess opening.
 11. The apparatus of claim 1, wherein the desiccantcontainer comprises a trough and a cover over the trough; the accessopening being in the cover; and a snap mechanism attaching the cover tothe trough.
 12. A plurality of the apparatus of claim 11, each of theapparatus including a respective trough portion and a cover portion; andeach of the cover portions of each apparatus having one of the airaccess opening openings and the air access openings have areas of atleast two sizes.
 13. The apparatus of claim 1, further comprising anoutlet opening in the desiccant solution container for enabling exit ofthe desiccant solution from the desiccant solution container, and aremovable plug in the outlet opening.
 14. The apparatus of claim 1,further comprising a hanging device for hanging the apparatus.
 15. Theapparatus of claim 1, further comprising a cartridge filled with theparticulate desiccant for providing the particulate desiccant in thedesiccant container, the cartridge having permeable walls permeable toatmosphere and to an aqueous desiccant solution.
 16. The apparatus ofclaim 1, wherein the desiccant container and the desiccant solutioncontainer are both of generally cylindrical shape.
 17. The apparatus ofclaim 1, wherein the desiccant container and the desiccant solutioncontainer are of generally parallelepipedal form.
 18. The apparatus ofclaim 1, further comprising a shield for at least partial shielding ofthe access opening to the desiccant container.
 19. The apparatus ofclaim 18, wherein the shield for the access opening comprises thedesiccant solution container.
 20. The apparatus of claim 19, furthercomprising the desiccant solution container being fixable in a positionwhich at least partially covers the access opening to the desiccantcontainer.